Treasure Valley Electrical Plan - Idaho Power...Distribution Substation Placement Once the TVBP...

Treasure ValleyElectrical Plan

Prepared by

System Planning DepartmentIdaho Power CompanyBoise, ID

October 2006

Idaho Power Company

October 2006 Treasure Valley Electrical Plan Page i

Table of Contents Table of Contents............................................................................................................................. i Executive Summary ........................................................................................................................ 1 Introduction..................................................................................................................................... 3 Technical Input ............................................................................................................................... 4

Idaho Power Distribution Planning Build-out Projection........................................................... 4 Distribution Substation Placement.......................................................................................... 4 138 kV Transmission .............................................................................................................. 7

Treasure Valley Growth............................................................................................................ 10 First Cut—A Load-Based Approach .................................................................................... 10 Second Cut—A Customer-Based Approach......................................................................... 10

Demand-Side Management (DSM) Effects on Load................................................................ 11 Treasure Valley Electrical System Capacity............................................................................. 12

Committee Input ........................................................................................................................... 14 Source Substations .................................................................................................................... 17 Hub Substations ........................................................................................................................ 18 500 kV Transmission Line Routes............................................................................................ 19 230 kV Transmission Line Routes............................................................................................ 20

Technical Analysis........................................................................................................................ 21 n-1 Reliability Criteria .............................................................................................................. 23 Line-Loading Criteria ............................................................................................................... 23 Modeling Results ...................................................................................................................... 24

ROW Analysis .............................................................................................................................. 24 Cost Estimates............................................................................................................................... 26

230 kV Transmission Line Costs.............................................................................................. 26 500 kV Transmission Line Costs.............................................................................................. 26 Hub Substation Costs................................................................................................................ 27 Source Substation Costs............................................................................................................ 28

Implementation Plan ..................................................................................................................... 29 Conclusions/Results...................................................................................................................... 30 Appendix A—List of Community Advisory Committee Members ............................................... 1 Appendix B—Comments & Suggestions Recorded During Mapping Exercises........................... 1 Appendix C—Load Density Based on Zoning ............................................................................... 1 Appendix D—Group Mapping Results .......................................................................................... 1 Appendix E—Group Drawings Similarities/Commonalities.......................................................... 1 Appendix F—n-1 Reliability Criteria Example.............................................................................. 1

Idaho Power Company

October 2006 Treasure Valley Electrical Plan Page 1

Executive Summary Treasure Valley is the center of growth in Idaho—a growth that has been nothing short of explosive in the past few years. The community as a whole is struggling to keep up with the influx of population that is straining services and forcing the small cities within Ada and Canyon counties to begin thinking like the larger cities that, in the past, they have resisted becoming. Like the various jurisdictions in the Treasure Valley, Idaho Power Company (Idaho Power) must also think like a more urban utility and make plans for a future with higher voltages, more generation and urban load densities, and land constraints that make it more and more difficult to deliver electricity to our customers. Land for substation sites and transmission line rights-of-way is becoming quite expensive and, in many cases, the most technically appropriate transmission line route is impossible to secure because of either jurisdictional or public resistance. Twenty years ago, Idaho Power could site substations and transmission lines in locations it felt were technically the best. This is no longer true. Social and environmental awareness have combined to make it imperative that much more be considered when siting any new infrastructure. The first step is getting buy-in from the people most affected by a project during the conceptual phase. Idaho Power must consult citizens, activists, and jurisdictional authorities prior to considering infrastructure improvements. Not doing so creates the risk that a project might be delayed for many years, and the electrical load Idaho Power is legally obligated to serve could have its reliability reduced. This is a similar dilemma to that faced by the Idaho Transportation Department (ITD) and the various highway districts in the valley; all must provide roads to move people and goods throughout the valley but sometimes find it nearly impossible to reach agreements with the citizens and jurisdictions that make the roads necessary. In the Treasure Valley, Idaho Power’s transmission lines are generally built along the sides of roads, so ITD’s and the highway districts’ problems are Idaho Power’s problems. In an effort to get ahead of the growth so that its plans are successful, Idaho Power is creating the Treasure Valley Electrical Plan (TVEP). The plan lays out the electrical infrastructure in the Treasure Valley from now through valley build out. This plan determines locations for major substations and transmission lines to serve the valley for many years to come and allows Idaho Power to plan individual projects without being concerned they will not fit into future plans. Think of it like connecting the dots, where the dots are substations and the connections are the transmission lines between the substations. If Idaho Power knows where the dots are, it can determine where the connections need to be and then attempt to gain consensus on the locations far in advance of the need. A lone dot with no way to get a line to it is in no one’s best interest. A Community Advisory Committee (CAC) was formed to advise Idaho Power in its initial efforts to site infrastructure in the Treasure Valley and was the first step in the long range planning process. The committee, made up of area planners, city and county leaders, industrial and business interests, special interest groups, advocacy groups, and general citizens, met regularly over a one-year period.

Idaho Power Company

October 2006 Page 2 Treasure Valley Electrical Plan

Idaho Power wishes to extend a heartfelt thank you to every member of the CAC. The time and effort the committee gave to this project will enable Idaho Power to go forward with plans to serve the Treasure Valley and gain public acceptance to the specific pieces that must, through further public collaboration, be put in place to make this plan a reality. This report is a result of the committee’s efforts and will serve as the basis for further studies to refine and stage future infrastructure improvements in the Treasure Valley.

Idaho Power Company


Introduction The Treasure Valley, defined in this study as the region consisting of Ada and Canyon counties, is undergoing a period of tremendous growth. Since 1990, valley population has increased nearly 45% and is expected to increase another 60% by 2030. The existing population is over 500,000 and is projected to reach over 800,000 in the next 25 years, with an ultimate build-out population projected at over 2.4 million people. In electrical terms, Idaho Power is adding about 50 megawatts (MW) of electrical load per year in the Treasure Valley which accounts for more than 80% of the load growth in the entire Idaho Power system. With this growth comes the need to expand and upgrade the valley’s electrical system. Major growth and transportation planning studies are presently taking place, and Idaho Power must also perform studies to respond to the growth with additional energy supplies. Because rights-of-way are becoming difficult to obtain, Idaho Power must be diligent in ensuring that high voltage transmission plans are included in future transportation plans and also ensure that proposed transmission line routes and substation locations are communicated to the various jurisdictions in the Treasure Valley. For these reasons, Idaho Power’s System Planning Department determined that the time was right for a wide-ranging plan for 500/230 kV and 230/138 kV substation locations and the 500 kV and 230 kV transmission lines to interconnect them within the Treasure Valley. This plan will serve as a roadmap for Idaho Power infrastructure in the Treasure Valley from now through valley build out and will be used as a background for shorter term (5-, 10-, and 25-year) studies. Updates to the plan will be made periodically with a formal review of the plan every 10 years. Idaho Power decided that one of the key aspects to the Treasure Valley Electrical Plan (TVEP) is that it would be thoroughly processed through public venues before it could be considered final. More specifically, the public process would be the starting point of all electrical supply plans and any resulting transmission rights-of-way and substation siting requirements. To address this requirement, a Community Advisory Committee (CAC) was formed to advise Idaho Power in siting infrastructure in the Treasure Valley. The committee, comprised of area planners, city and county leaders, industrial and business interests, special interest groups, advocacy groups, and general citizens, met monthly over a one-year period. A list of CAC participants is provided in Appendix A. To aid in siting transmission along future transportation corridors, the TVEP has attempted to incorporate the results of the ongoing Blueprint for Good Growth and Communities in Motion studies. Though neither of these studies is in final form, there is much information already developed that can be used by Idaho Power for Treasure Valley transmission plans.

Idaho Power Company


Technical Input Idaho Power Distribution Planning Build-out Projection The TVEP used, as its basis, a study performed by Idaho Power’s Distribution Planning Department in 2001 (updated in 2003) titled “Treasure Valley Build-out Projection” (TVBP). That study evaluated land use and population projections to determine the electrical load in the Treasure Valley at a point in the future determined to be the valley’s ultimate build out. The Treasure Valley Build-out Projection identified four growth drivers:

• Customer/Population • Industry • Transportation • Natural Resources

The first three drivers are all quite interdependent in that growth in any one of them can cause growth to occur in the others. As growth occurs in any or all of the drivers, natural resource usage is increased. The study considered land to be the most limiting natural resource in that growth will be limited by the availability of land and, to that end, land use projections are the basis for the ultimate electrical load prediction at build out. Water might also be considered a limiting resource; however, experience throughout the West indicates that cities find ways to grow even in the absence of an adequate water supply. Through land-use projections, the TVBP estimated that the ultimate build-out load for the Treasure Valley is 7,200 megawatts (MW). This number was verified through a population projection to a point past 75 years. Using a 2% annual growth rate over the 75-year period and applying an estimated average electrical load of 4.3 kW/person (averaged across all customer classes), a build-out load of 7,000 MW was calculated. This is quite close to the 7,200 MW build-out load calculated through land-use projections. The TVEP expanded on these estimates and is discussed later in this report.

Distribution Substation Placement Once the TVBP study determined the ultimate build-out population and electrical load, an effort was then made to place electrical load in appropriate locations throughout the valley. The load needed to be spread between all the various customer classes, such as residential, industrial, commercial, and agricultural. The Treasure Valley was divided into electrical load density zones with the assumption that the location of new load will generally follow transportation corridors with some spot-density increases near smaller communities such as Kuna and Middleton. The highest electrical load density will be near Interstate 84 and will generally become less dense as it progresses further from I-84.

Idaho Power Company


The valley was divided into three general load densities:

D1—High density; urban corridor along I-84 D1 = 12 MW/mi2 D2—Suburban density; area surrounding D1 D2 = 7–8 MW/mi2 D3—Rural; area surrounding D2, bounded by the Snake River, public lands, and mountains D3 = 3–4 MW/mi2

Figure 1 shows the density zones and how they were laid out.

.-, 84

.-, 8 4

ôó55

ôó2 1.-, 84

Urban (12MW/mi

Suburban (7-8MW/mi2) Rural

(3-4MW/mi2)

Rural (3-4MW/mi2)

Suburban (7-8MW/mi2)

Figure 1. Treasure Valley Density Zones

Based on the above densities and the area determined appropriate because of land characteristics, an estimate of the needs for distribution substations at build out was made and appropriate locations were determined. Idaho Power’s Distribution Planning Department began with the assumption that each distribution substation can be assigned a service area of 8 mi2, shaped like a diamond, and, in general, would serve a load of 80 MW. This size and shape was established previously by the Distribution Planning Department. The service area diamonds were placed such that land coverage near the I-84 corridor was total, while the coverage decreased progressing outward toward the fringes of the valley.

Idaho Power Company


Once the various distribution substation coverages were placed, the task was to precisely locate each substation at a street intersection that might have land available for use. Ideally, the substation would be located in the center of the coverage area. However, this was not always possible or desirable; in many cases, the actual substation placement was well off-center. A couple of additional distribution substations were added to cover some anticipated load, which is shown in Figure 2.

Figure 2. Existing and Future Treasure Valley Distribution Substations

The actual load served out of each substation was adjusted such that those located near high-density areas would sometimes serve more than 80 MW.

Idaho Power Company


138 kV Transmission After placing the Distribution substations, a methodical means to interconnect them with transmission was necessary. The existing transmission system in the Treasure Valley consists of a 69 kV and 138 kV network fed from 230 kV transmission lines from the southeast and northwest. The 69 kV portion of the network is in the process of being replaced with 138 kV. Figure 3 shows the existing Treasure Valley transmission network.

Figure 3. Existing Treasure Valley Transmission Network

Idaho Power Company


A number of different transmission schemes were evaluated that would offer fully redundant feeds to a majority of the Treasure Valley Distribution substations. In the end, it was determined that the best configuration to use was a scheme Distribution Planning named the Loop Model. The components of the Loop Model are the Hub Substation (load center) and its 138 kV transmission grid. Figure 4 shows this type of configuration.

Figure 4. 138 kV Loop Transmission Model

Idaho Power Company


The source of power to a Hub Substation consists of two or more 230 kV transmission lines. These 230 kV lines are linked to other Hub Substations and with major Source Substations that act as delivery points for power being fed into the valley. The Hub Substation transforms the voltage of the 230 kV transmission down to 138 kV for transmission to the Distribution substations via the loop transmission. Each loop will have three to five Distribution substations connected to it. Each Distribution substation will have two 138 kV transmission lines feeding it, sized such that if one of the lines is not available, the other can carry the entire load. Figure 5 shows the projected 138 kV Loop transmission system at build out. Note that the Loop transmission configuration is undergoing reevaluation, and the scheme may be modified in the future to reduce the amount of right-of-way that must be purchased to supply a fully redundant 138 kV transmission system. Even if the Loop transmission system is modified in the future, the Hub and Distribution substation locations should remain the same.

Figure 5. Projected 138 kV Transmission at Build Out

Idaho Power Company


Treasure Valley Growth The TVEP expanded on the methods used in Distribution Planning’s TVBP for ultimate build-out population/electrical load estimates by applying two additional methods, both using comprehensive plans from the cities of Boise, Eagle, Garden City, Meridian, and Nampa. Each of these city’s comprehensive plans assigns a zoning for the land inside the city’s future city limits or areas of impact. Examples of zoning are R-4 (four houses per acre), Commercial and Industrial, Office, etc. Smaller cities, such as Star, Middleton, and Kuna, were assumed to have a medium density zoning. Caldwell, which did not have GIS coverages that were usable in this analysis, was assigned zoning similar to Nampa’s average zoning. Almost all other land in the area of study was assigned zoning for agricultural use. It must be noted, however, that areas of impact are not static. These boundaries change as cities expand. Because of this, a level of uncertainty must be given to the following calculations.

First Cut—A Load-Based Approach The first method using the comprehensive plan approach assigned a loading in kilowatts-per-square mile (kW/mi2) based on the assigned zoning. The loading based on zoning was estimated in previous studies performed by Idaho Power’s Distribution Planning Department. Taking the kW/mi2 value for each zone and multiplying it by the area associated with each zoning class, a value of load in kilowatts was determined for each zoning class. Appendix C—Load Density Based on Zoning shows power density assignments for various zoning in the valley. Using the assumption that smaller communities will exhibit a medium density and assigning Nampa’s average density to Caldwell, a total area (in square miles) and a total load was estimated for all cities in the Treasure Valley. The area of study encompasses 1,100 square miles; subtracting off the city square mileage yielded the amount of agricultural land remaining to add to the analysis. It is assumed that the agricultural land will be completely residential at build out with two-acre lots occupying what is now agricultural. In the end, an estimated load value of 7,197 MW was calculated. Through previous studies conducted by Idaho Power, it was calculated that electricity consumption in the Treasure Valley is about 3 kW per person. Dividing 7,197 MW by 3 kw/person yields a total population of about 2.4 million people. Note that the 3 kW per person number differs from the number used in the TVBP (4.3 kW per person). This is because the 4.3 kW per person number used was based on a loading that encompassed the entire western part of Idaho Power’s service area instead of only the Treasure Valley, thus causing an over-estimation. The present study uses only the populations of Ada and Canyon counties to estimate the load per person.

Second Cut—A Customer-Based Approach In the Customer-Based approach, everything other than residential zoning was ignored and only the valley population at build out was estimated. It was assumed that people will only live in a city’s residential zoning or in the agricultural land outside the main cities, and it was also assumed that people cannot live in areas zoned industrial, office, or commercial. Residential zoning is straightforward. An R-4 zone implies 4 houses per acre, while an R-1 zone implies 1 house per acre. Using the same method as the Load-Based approach, all homes/apartments across the entire area of study were added up. This calculation yielded the total number of Idaho

Idaho Power Company


Power customers at build out (not a population value). Using Census year 2000 data and verifying the data with existing Idaho Power customer base, there are about 2.5 people per Idaho Power customer in the Treasure Valley. Adding together all the customers per zoning class, it is estimated there will be 2.65 million people at build out, using approximately 7,964 MW. This value is a little higher than what was estimated in the Load-Based approach above. There can be many reasons for this:

1) Golf courses will be located inside residential zones, lowering the number of houses in a zone.

2) Many new subdivisions will have parks, ponds, and meandering sidewalks that will consume land where there could have been houses.

3) Zoning is a maximum density (in most cases), and developers may choose to develop at a lower density.

The number in the Customer-Based approach would ideally be less than the number in the Load-Based approach because of all the bedroom communities—such as Marsing, Emmett, and, in some cases, Mountain Home—where people reside but drive to work in Boise. The number in the Customer-Based approach could easily go down 10% by factoring in parks and golf courses, bringing the population number to about 2.4 million with a load of 7,178 MW, which is much closer to the estimates calculated in the Load-Based approach. Table 1 shows a comparison of the various load projections made in both the TVEP and Distribution Planning’s TVBP. The load projections are quite similar in all four methods, giving a good level of confidence to the projections. Table 1. Population and Load Projections

Load Population

TVBP Method 1 7,200 MW N/A

TVBP Method 2 7,000 MW 1.6 M people @ 4.3 kW/person

TVEP Load-Based Approach 7,197 MW 2.4 M people @ 3 kW/person

TVEP Customer-Based Approach 7,964 MW 2.65 M people

In the shorter term, a forecast of electrical load was made to the year 2030, using an internal Idaho Power population forecast derived from an internal Idaho Power model. Population for the two-county area (Ada and Canyon) is projected to be 874,439 people. Again, based on the internal model, Idaho Power projects an estimated electrical load in 2030 of about 2,620 MW.

Demand-Side Management (DSM) Effects on Load Demand-Side Management (DSM) activities are those which involve actions on the demand- or customer-side of the electric meter, either directly or indirectly caused by the utility. The purpose of these activities is to change the configuration or magnitude of the load shape. Through aggressive use of DSM technologies, Idaho Power expects new load to be reduced by between 20 and 30 percent. Taking into account the expected DSM effects on new load growth, the Treasure Valley electrical load can be reduced by 1,600 MW, giving a planning load at build out

Idaho Power Company


of 5,600 MW, as shown in Table 2. This is the base electrical load number that will be planned for at valley build out. While this reduction is certainly aggressive, the expectation is that Idaho building standards will improve dramatically in the coming years and, in particular, Treasure Valley building practices will lead the way to much more energy-efficient housing and businesses. Additionally, Idaho Power demand response programs will mature and act to reduce the peak load by significant amounts. Table 2. Total Planning Load Including DSM

Build Out

Population 2,400,000

Electrical Demand 7,200 MW

DSM Potential (20–30% of new load) 1,600 MW

Total Planning Load 5,600 MW

In November 2005, the CAC was given an educational presentation on Demand-Side Management and was then broken into discussion groups to discuss the following questions (some CAC member responses follow the questions): Do you see any barriers that would prevent Idaho Power from achieving the expected DSM results shown in the presentation?

• Lack of education • Idaho Power’s inexpensive rates • Cost of DSM, cost/benefit • Tough to get code changes

What would it take to exceed these expected results? • Provide more education • Regulatory changes to building codes and comprehensive plan policies • Political support • More incentives to participate

How could Idaho Power encourage community support of DSM? • More incentives to participate • Education of builders, realtors, political leadership, residents, and businesses • Expand conservation weatherization programs • Use power plant permitting process to dialogue with the public

Treasure Valley Electrical System Capacity Idaho Power’s transmission system—the high voltage lines that transmit electrical energy from generating plants to local load and among utilities to ensure a high degree of reliability—is part of an overall regional transmission grid operated throughout the western United States. From this high-voltage grid, local load is served by delivering the power to several key points in the Treasure Valley at 230,000 volts and then stepped-down to lower transmission voltages for delivery to distribution substations.

Idaho Power Company


Planning of the transmission grid is based on “criteria,” or standards, established by the North American Electric Reliability Council (“NERC”), by the Western Electricity Coordinating Council (“WECC”) and by Idaho Power. The NERC and WECC planning standards apply primarily to the high-voltage (230 kV and above) system. This system includes the electric generation resources, transmission lines, and interconnections with other electric utilities. The transmission system must be capable of performing under a wide variety of expected system conditions and must be planned to withstand probable forced outages known as “contingencies.” The NERC/WECC standards require that each utility member continually keep the system in a secure state (able to withstand the next contingency), even after one or more contingencies have already occurred. The Idaho Power standard is more focused on lower-voltage sub-transmission facilities. The Treasure Valley area is continuing to grow. In the near future, the sustained growth will cause transmission limits to be exceeded during peak load hours, which in the Treasure Valley occur on summer afternoons when air conditioner use is at its highest. If no system improvements are made, power outages will result when Idaho Power has relatively minor emergencies, such as a single transmission line, transformer, or generator being removed from service. The 2005 summer peak load in the Treasure Valley area was about 1,800 MW. Idaho Power currently estimates a yearly growth of 50 MW per year or approximately 2,100 MW by 2012. The total capacity of the transmission feeding the Treasure Valley is about 2,200 MW during summer peak. Allowing for some inaccuracy in the load forecast, new infrastructure needs to be in place by 2012. To accommodate this expected demand growth, a combination of several measures will have to be utilized, including DSM (voluntary load curtailment), generation resource additions (either distributed or in large fixed plants), and transmission expansion. Idaho Power is pursuing the implementation of an air conditioner cycling program which will reduce the Treasure Valley load by about 40 to 50 MW at peak, thereby delaying—but not eliminating—the need for transmission capacity improvements. The Treasure Valley transmission system has conditions, or triggers, which will require transmission capacity expansion after DSM and resource additions have been accounted for. These triggers can be categorized into four separate, but related, issues:

1. When load in the west side of the Treasure Valley (Meridian, Nampa, Caldwell) reaches about 850 MW, an additional 230 kV line will be needed, feeding into the western end of this area.

2. When load in the northern Treasure Valley loop (Boise Bench–Locust–Caldwell) reaches about 450 MW, an additional 230 kV line into this loop will be needed.

3. When load in the southern Treasure Valley loop (Boise Bench–Happy Valley–Nampa–Caldwell) reaches about 300 MW, an additional 230 kV line into this loop will be needed.

4. When total load in the Treasure Valley reaches 2,100 MW (assuming an appropriate solution to trigger 1), a new feed/source from outside the valley will be needed.

Idaho Power Company


The Treasure Valley presently has two source points: 1) Caldwell on the west and 2) Boise Bench on the east. Both Caldwell and Boise Bench sources have reached their ultimate capacity and are unlikely to be economically and reliably expanded. New source points to the north and south of the Treasure Valley would minimize the necessary number of new transmission line miles in the valley. Two reinforcement alternatives exist: 1) connecting to the existing Boise Bench–Brownlee 230 kV lines between Eagle and Emmett and 2) connecting to the Midpoint–Summer Lake 500 kV line near the Snake River south of Nampa. The 230 kV option adds 400 to 500 MW; the 500 kV option adds about 800 MW, and the two combined will ultimately add approximately 1,600 MW of capability. The 230 kV option is expected to be less costly and, on a dollars-per-MW-served metric, is also a more economical alternative to the 500 kV source. Ultimately, additional demand-side management and both reinforcement options will be necessary in the near term (30-year horizon). Beyond the near term, the Treasure Valley will require major new sources—whether they be local generation, transmission, or a combination of the two. One of the comments made by the CAC was that Idaho Power should remain vigilant for any significant changes in technology that might cause the present plan to become obsolete. Distributed generation is one such technology shift that could significantly decrease Idaho Power’s load and reduce or eliminate the need for more infrastructure. While this is very true and Idaho Power constantly monitors these new technologies, the only prudent course of action in the short term is to plan for the long term, using present technologies with the knowledge that long-term plans must remain dynamic in order to allow for new technologies and their effect on Idaho Power’s system. Idaho Power will periodically update this plan and will adjust as necessary to accommodate any technology shifts that may occur.

Committee Input The CAC started in August 2005 with a bus tour of Idaho Power facilities. The bus tour began a series of primarily educational meetings that were held monthly (excluding December 2005) through February 2006. Through these educational sessions, the CAC was introduced to electrical generation, substations, transmission, demand-side management, and regulatory affairs. Additionally, the CAC was presented with an in-depth view, from production to delivery, of Idaho Power’s system. Using the education gained from the meetings held between August and February, the CAC set to work in March and April to lay out proposed Treasure Valley transmission routes and substation sites. Idaho Power used RBC, Inc., of Boise to facilitate the CAC meetings. To support the layout sessions, the committee was given a bubble diagram (Figure 6) representing the various substation and transmission needs in the Treasure Valley. The bubbles and lines were not location-specific in that the bubbles (substations) and lines showed some necessary connections while suggesting only general geographical locations in the valley. The bubble diagram was built up, step-by-step, from existing conditions to build out, without referencing the order in which the various substations and lines should be built.

Idaho Power Company


M

gen

Treasure Valley Build-Out

S/H

Mt. Home

Ontario

CH

H

S

CH

gen

M

Southwest TVPacifiCorp

Brownlee

Northwest Orchard

Boise Bench

Midpoint

Midpoint 500kV

Caldwell

Locust

S

H

Cloverdale

Happy Valley

Bowmont Mora

S Boise S/H

Existing Transmission Line Future Transmission Line Future 500 kV Transmission Line

H

S New Source C Converted Distribution

to Hub Substations

New Hub Substations

Nampa

Sand Hollow

Middleton Existing Source/Hub Substations

S/H

E/H Existing Hub Substations

Homer

Dry Creek

Western Canyon County

Home-dale

S

CH

H

E/H

H

CH CHS

S

CH

CH

Figure 6. Treasure Valley Build-out Bubble Diagram

For simplicity, Idaho Power staff defined two types of substations for the committee’s consideration. Source Substations—Deliver bulk power to the Treasure Valley. Power arrives at a Source Substation at 500 kV and is stepped-down by transformers to 230 kV. Hub Substations—Act as the supply point for the 138 kV transmission loops identified in Distribution Planning’s TVBP. Power arrives at a Hub Substation at 230 kV and is stepped-down by transformers to 138 kV. Idaho Power recommended placement of four Source Substations and 15 Hub Substations. The committee was then broken into six different groups; each group was given a large aerial photograph of the Treasure Valley. Each group then laid out preferred Source and Hub substation sites and sited preferred 230 kV and 500 kV transmission line routes to interconnect the substations. Appendix B contains comments and suggestions from the various groups that were recorded during the mapping exercises.

Idaho Power Company


Idaho Power staff took these layouts and put them in electronic form. Figure 7 shows the results from one of the groups and Appendix D contains drawings from each group. Idaho Power staff then took the various drawings and compared them, noting similarities and differences between each. Again, the similarities and differences were put in electronic form and the resultant drawings can be found in Appendix E—Group Drawings Similarities/Commonalities. In order to reach consensus on a final layout, Idaho Power staff asked the CAC if some substation locations and line routes could be recorded as general locations and routes instead of being more geographically specific. The committee agreed to this proposition.

Figure 7. Group 1 Mapping Results

Idaho Power Company


Source Substations Figure 8 shows Source Substation groupings that were deemed acceptable to the committee. The blue-shaded areas are general locations where the committee agreed that a Source Substation could be placed, thus giving some latitude to Source Substation locations. Most of the groups chose to locate five Source Substations instead of the recommended four. While increasing the costs for Source Substations, these placements would also reduce the number of line miles associated with the 230 kV transmission emanating from the Source Substation, thus making the overall cost approximately equal.

Figure 8. Mapping Results—Source Substation Locations

Idaho Power Company


Hub Substations All but three Hub Substations were exactly located. That is, most groups agreed on exact locations where Hub Substations should be located. Figure 9 shows the agreed-upon locations and also three green-shaded general areas where, like the Source Substations, the committee agreed that a Hub Substation could be placed. The red circles refer to Hub Substation locations, where at least three of the groups agreed upon an exact location. The blue, numbered circles indicate substation locations uniquely identified by the various groups. In nearly all cases, the groups chose to locate Hub Substations coincident to existing Idaho Power distribution substations.

Figure 9. Mapping Results—Hub Substation Locations

Idaho Power Company


500 kV Transmission Line Routes The various groups were unanimous in their choices for southern and northeastern 500 kV transmission line routes. For the southern route, every group determined that the Idaho Power 500 kV transmission should follow the same route as the existing PacifiCorp 500 kV line that runs through the southern part of the valley. For the northeastern route, all groups agreed that the 500 kV transmission should use the same right-of-way as the existing Idaho Power 230 kV transmission coming into the valley from the Hells Canyon Complex, the three-dam complex comprised of Brownlee, Hells Canyon, and Oxbow. For the southeastern route, the committee agreed to a swath that encompasses the existing Idaho Power 230 kV transmission right-of-way coming into the valley from Midpoint Substation. In the western part of the valley, the committee agreed to a swath that covers the area between the Oregon side of the Snake River to the west and State Highway 95 to the east. In the northern part of the valley, the committee agreed to a five-mile-wide swath north of Eagle and south of Emmett. Figure 10 shows the agreed-upon 500 kV transmission line routes.

Figure 10. Mapping Results—500 kV Transmission Line Routes

Idaho Power Company


230 kV Transmission Line Routes There were not many similarities between the groups as to 230 kV transmission line routes. Only a few routes could be identified where three or more of the groups agreed. Because of this, the committee was asked if Idaho Power could choose any of the routes recommended by the groups for 230 kV transmission lines. The committee agreed to this proposition, with the following exceptions:

• Do not run 230 kV transmission through downtown Eagle. • Stay away from the Boise Bench. • Limit the number of lines running through the Pierce Park/Dry Creek areas. • Avoid State Street.

Figure 11 shows the various line routes identified by the groups. Note that the exceptions shown above are shown in this drawing but are not considered for modeling.

Figure 11. Mapping Results—230 kV Transmission Line Routes

Idaho Power Company


Technical Analysis Based on the results from the CAC mapping exercises, Idaho Power staff developed a scenario for analysis that incorporates the recommended substation locations and line routes. The Analysis Layout shown in Figure 12 consists of:

• 5 Source Substations • 15 Hub Substations • 500 kV transmission loop around the valley that interconnects the Source Substations • 230 kV transmission to interconnect the Hub Substations

Figure 12. Analysis Layout

The scenario chosen should give nearly worst-case results since it represents more line miles than any of the individual maps. This, of course, is not the only scenario that would fit within the recommendations of the CAC. There are numerous choices for 230 kV and 500 kV transmission lines, as well as some latitude for locating certain substations. All of the substations shown in the Analysis Layout are named. If a Source or Hub substation is to be located where there already exists a distribution substation, the distribution substation’s name is used. If a substation is to be

Idaho Power Company


located where no distribution substation presently exists, the name is derived from its relevant location within the Treasure Valley. From the Analysis Layout, Idaho Power staff developed a computer model using PowerWorld power flow software to evaluate the power flow that would result from this scenario. The power flow model used as its basis a case that includes Idaho Power generation at the Hells Canyon Complex, a dummy generator located at Midpoint Substation to represent generation entering Idaho Power’s system from the east, and a dummy generator at Summer Lake Substation to represent power imports from the west over the PacifiCorp 500 kV transmission line. Additionally, a dummy generator was placed at a location near Lower Monumental Substation in Washington to represent a possible future interconnection point. Placing generation distant from the valley gives a more realistic model than just placing it directly at the 500 kV substations located around the valley. It is understood that this distant generation and the transmission that connects to it is beyond the scope of this present study. However, it is felt that modeling the generation remotely from the valley will give important insight into how the interconnections to the valley are performed. Two 500 kV transmission lines are modeled from Midpoint Substation, one entering the Treasure Valley at Melba and the other at SW Canyon substation. One 500 kV transmission line is modeled from Lower Monumental that enters the Treasure Valley at Sand Hollow. A connection to the PacifiCorp 500 kV transmission line is made at Melba, giving a total of four 500 kV sources to the valley. Table 3 shows the sources entering the Treasure Valley in the model. Table 3. Treasure Valley Sources

Source Substation Treasure Valley

Substation Line Name Voltage

Brownlee Boise Bench Brownlee 1 230 kV




Brownlee Ontario Brownlee 5 230 kV

Midpoint Boise Bench Midpoint 230-1 230 kV

Midpoint Boise Bench Midpoint 230-2 230 kV

Midpoint Dram Midpoint 230-3 230 kV

Danskin Mora Danskin 230 kV

Summer Lake Melba Summer Lake 500 kV

Midpoint SW Canyon Midpoint 500-1 500 kV

Midpoint Melba Midpoint 500-2 500 kV

Lower Monumental Sand Hollow Lower Monumental 500 kV

The existing 230 kV transmission lines within the Treasure Valley are modeled with their capacities and lengths as they exist today. New 230 kV transmission lines within the valley are

Idaho Power Company


all rated a standard value that is adequate to carry the electrical current that will naturally flow through them. If, through modeling the system, an existing transmission line is found to be undersized, its capacity will be increased to the standard value mentioned above with the assumption that it is possible to upgrade that particular line. Attention has been paid to developing the model to ensure that the power flowing on the existing 230 kV lines feeding into the Treasure Valley is relatively the same at build out as it is in 2006. In so doing, new load is supplied by the new 500 kV transmission lines feeding into the valley and the existing lines are not overloaded. The Treasure Valley electrical system is modeled only down to the 230 kV level. While distribution substations are supplied via 138 kV transmission lines that feed out of the Hub substations, their loads are aggregated up to the 230 kV level and are shown in the model as being fed from the Hub Substations. For an extra-high voltage plan, this will give adequate and accurate results. The PowerWorld model shows how the power flows on the system. It is used to evaluate voltage levels at all substations, reactive and real power flows, whether the lines are adequately sized, and whether or not the model meets n-1 reliability criteria.

n-1 Reliability Criteria Idaho Power must adhere to what is known as an “n-1” criterion. This means that for multiple transmission lines delivering power to the same point, if one of the lines goes out of service, the remaining lines must be able to carry both the load they were carrying before the event, plus the load carried by the line that is out of service. This is true even if the line with the highest capacity is the one that goes out of service and only holds true for major transmission lines. See Appendix F—n-1 Reliability Criteria Example for an example of the n-1 criteria. The multiple 230 kV transmission lines in the Treasure Valley and the 230 kV and 500 kV transmission lines feeding into the valley can all be considered parallel paths in that if one of the lines is out of service, none of the remaining lines can be overloaded and none of the substations can have voltages lower than an acceptable level. The maximum line-loading criteria used under n-1 contingencies in this study is 100%. This means that if the system experiences one line out of service, no remaining transmission line can be loaded to more than 100% of its capability. The minimum voltage acceptable under an n-1 contingency is 90%, meaning that the voltage cannot be less than 90% of the normal value at any given substation. For a 230 kV substation, this would mean that the minimum voltage could be 0.90 x 230,000 volts = 207,000 volts.

Line-Loading Criteria The only requirement applied to the amount of power a transmission line is allowed to carry under normal operating conditions is that it cannot go beyond 100% of its capacity. If a line is loaded to 100%, it still must be able to meet the n-1 criteria described above; thus, normally, a line will not be designed to carry 100% of its capacity during normal operating conditions.

Idaho Power Company


Modeling Results The model using the PowerWorld power flow software indicates that the system, as recommended by the CAC, will perform within the set criteria. No lines within the Treasure Valley became overloaded during an n-1 contingency, nor did any substation’s voltage fall below 90% during an n-1 contingency. It was necessary to install capacitors in certain substations to improve the voltage profile during both normal and n-1 operations. Capacitors are large power devices found in substations that act to increase the voltage at a substation and improve the flow of power over transmission lines. It is normal to install capacitors throughout a power system. Today, Idaho Power has many capacitors installed at various substations and even on many distribution lines. The capacity of the existing Ontario to Caldwell 230 kV transmission line was increased because of overloads that occurred during an n-1 contingency. This was the only existing line that needed to be adjusted for build out.

ROW Analysis As discussed previously, the CAC chose many different routes in which Idaho Power could place 230 kV and 500 kV transmission lines. Most of the routes follow existing road and rail rights-of-way, and some follow routes with no existing rights-of-way. Some of the routes follow existing electrical transmission corridors which will mean either replacing/upgrading the existing infrastructure or expanding the corridor’s width. Securing the rights-of-way necessary for all the transmission slated for the Treasure Valley will likely prove the most challenging task facing Idaho Power as it constructs electrical infrastructure toward the valley build-out scenario. Transmission line rights-of-way can be obtained using any of the following methods:

• Easement—An easement gives Idaho Power the right to use the land for a specific purpose. Idaho Power acquires rights from private property owners through negotiations. The easement specifies rights and restrictions on Idaho Power’s use of the land while the property owner retains ownership of the land. This is the most common arrangement.

• Fee Title Ownership—A landowner may sell the land needed for the transmission line to Idaho Power. Idaho Power then owns the property, receiving title through a deed.

• Permit—Idaho Power makes application to the appropriate agency for a permit to place the necessary facilities across public lands.

• Eminent Domain or Condemnation—If the landowner and Idaho Power are unable to negotiate a price for an easement or purchase of property, Idaho Power may exercise its rights under state law to take the easement or property through court action. The court then determines the fair price to be paid based on testimony provided by Idaho Power and the property owner’s witnesses.

Idaho Power Company


If a transmission line route follows a transportation corridor, Idaho Power can either place the transmission line within the road right-of-way or purchase a private easement along the road right-of-way. Idaho Power usually chooses to secure a private easement because if the road is widened in the future making it necessary to move the line, the cost of moving the transmission line would fall upon the agency widening the road. If the line were within the road right-of-way, Idaho Power would have to bear those costs. Placing a transmission line within a railway easement can present special problems. Rail companies are sometimes hesitant to allow high-voltage transmission lines to be installed too near their rail lines because of concerns that their close proximity could allow electricity to couple onto the rails and cause personnel safety issues. Idaho Power currently uses part of the rail corridor right-of-way through Boise for 138 kV and 230 kV transmission and is seeking permission to use the Union Pacific Railroad’s (Union Pacific) rail corridor through Nampa for 230 kV transmission. Union Pacific is currently studying this request, and the results should be available soon. No estimate is made in the TVEP study concerning transmission rights-of-way cost because of the tremendous uncertainty involved in each corridor identified. Very few of the corridors identified by the CAC are in existing transmission corridors and, as such, it is uncertain which method of securing the right-of-way would be used that far in the future. Additionally, some corridors may simply be unavailable due to environmental issues, proximity to schools, or other existing and planned land uses. In January 2006, the CAC was given an educational presentation on transmission right-of-way issues and was then divided into groups to discuss the following questions (some responses follow the questions):

1. What are important issues to consider when locating transmission lines in the Treasure Valley?

• Build transmission lines along or through undeveloped corridors or undevelopable ground where possible.

• Secure corridors early—sooner rather than later. Use a 10-year, at minimum, planning horizon.

• Locate transmission corridors with transportation corridors. Use established freeway and highway corridors.

• Utilize public lands where possible for 500 kV lines. • Consider the value of properties adjacent to transmission corridors. • Make sure the proposed or approved corridors are included on planning maps or

future land acquisition maps. Work towards clarity on local comprehensive committees and plans.

• Avoid residential areas, schools, ridge tops, high population areas, and projected growth areas.

2. Where would you like to see transmission lines enter the Treasure Valley? • Northwest and southeast • Along railroad corridor • Kuna–Mora Road

Idaho Power Company


• Use existing Brownlee–Boise Bench corridor • Follow existing PacifiCorp 500 kV line route • From the north, following Highway 16 • Use existing Midpoint–Boise Bench corridor

Cost Estimates The following cost estimates are based on substation costs and transmission line costs associated with the Analysis Layout discussed in the preceding section. These costs likely represent high-end estimates, since this scenario has more transmission line miles embedded in it than any of the individual scenarios developed by the various CAC groups. Costs estimates are broken down into four components:

1. 230 kV transmission cost 2. 500 kV transmission cost 3. Hub Substation cost 4. Source Substation cost

230 kV Transmission Line Costs The cost per mile of 230 kV transmission is based on a single-circuit, single-pole structure. If two 230 kV circuits are placed on the same tower, the cost is reduced significantly; however, to be conservative, only single-circuit arrangements are considered here. If it is envisioned that an existing transmission line will be upgraded to meet increased requirements at build out, costs are assigned to that line the same as if it were new, since the towers would likely need to be replaced over time anyway. In 2006 dollars, the cost for a 230 kV single circuit transmission line is approximately $325,000 per mile, not including right-of-way. Right-of-way costs are very difficult to determine and are dependent on the type of right-of-way. See the section above for a more complete discussion. There are approximately 275 miles of new 230 kV transmission included in the build-out plan. At a labor and materials cost of $325k per mile for a single-circuit 230 kV line, the build-out cost associated with 230 kV transmission in the Treasure Valley is approximately $89M. Right-of-way costs can increase this amount significantly, depending on where the line is constructed. Of course, these lines will not all be put in place at once, but these costs give an idea looking into the future of their present value.

500 kV Transmission Line Costs The cost per mile of 500 kV transmission is based on a single-circuit, single-pole structure. Idaho Power would not likely install more than one 500 kV circuit on a single tower because of reliability concerns, since it would be very difficult for the system to survive an outage of two

Idaho Power Company


500 kV circuits at the same time. Thus, every effort will be made to geographically separate 500 kV circuits. In 2006 dollars, the cost for a 500 kV single-circuit transmission line is approximately $750,000 per mile, not including right-of-way. See the section on Right-of-Way Analysis for a discussion. All 500 kV transmission in the Treasure Valley will be new, and there are approximately 161 miles in the build-out plan. At a cost of $750k per mile for a single-circuit 500 kV line, the build-out cost associated with 500 kV transmission is approximately $120M. Right-of-way costs will increase this amount by as much as 100%. Again, this is putting a present value amount on money that will mostly be spent far into the future.

Hub Substation Costs The Treasure Valley presently has four existing Hub Substations: Boise Bench, Locust, Nampa, and Caldwell. Nearly all the rest of the Hub Substations will be built on the sites of existing distribution substations and, typically, both types of substations will coexist on the same piece of land. In the case where substation sites will coexist in a location already inhabited by a distribution substation, land costs are considered to be zero. While it might be necessary to purchase some additional land around an existing distribution substation site, the cost would be relatively small. The land requirement for a typical Hub Substation is five acres. A Hub Substation will consist of line terminals, transformers, buswork, and a control building. The present value cost estimate for a Hub Substation is approximately $13,000,000, exclusive of the land cost. Costs for the various Hub Substations are estimated in Table 4. Equipment Cost shown in this table includes the cost to construct.

Idaho Power Company


Table 4. Hub Substation Costs

Hub Substation Equipment Cost

Sand Hollow 230 $13,000,000 Hwy 16 $13,000,000 Hidden Springs $13,000,000 Middleton $13,000,000 Caldwell Existing Homedale $13,000,000 Huston $13,000,000 Locust Existing Cloverdale $13,000,000 Nampa Existing Happy Valley $13,000,000 Boise Bench Existing Bowmont $13,000,000 Mora $13,000,000 South Boise $13,000,000 Total $143,000,000

Source Substation Costs There are currently two Source Substations supplying the Treasure Valley: Boise Bench and Caldwell. Both of these are 230 kV Source Substations, and neither one is a likely candidate for 500 kV transmission. However, the 230 kV transmission lines presently feeding into them will stay in place and continue to serve as sources to the Treasure Valley. All five future Source Substations will require new land as they are not envisioned to be built where there currently exists either a Hub or distribution substation. The land needed for a Source Substation can be as high as 10 acres. Like a Hub Substation, a Source Substation will consist of line terminals, transformers, buswork, and a control building. The present value cost estimate for a Source Substation is approximately $25,000,000, exclusive of the land cost. Costs for the various Source Substations are estimated in Table 5. Equipment Cost shown in this table includes the cost to construct.

Idaho Power Company


Table 5. Source Substation Costs

Source Substation Equipment Cost

Sand Hollow 500 $25,000,000

Pearl $25,000,000

Southwest Canyon $25,000,000

Melba $25,000,000

South Ada $25,000,000

Total $125,000,000

The Pearl Source Substation will likely be built at 230 kV in the near future and later add 500 kV when the 500 kV transmission loop is built around the valley. The $25M cost estimate should still suffice in present value terms. Table 6 breaks down the costs discussed in the preceding paragraphs. Table 6. Cost Estimates

Component Equipment Cost

230 kV Transmission $89,000,000

500 kV Transmission $120,000,000

Hub Substation $143,000,000

Source Substation $125,000,000

Total $477,000,000

Implementation Plan The next step after this study is published is to get these results included in the comprehensive plans of the various jurisdictions throughout the Treasure Valley. In fact, this is one of the primary purposes of the TVEP study. While this will not, by any means, ensure that the identified transmission lines and substations will automatically receive city and county approvals, it will give notice to the jurisdictions, as well as valley businesses and citizens, that a given roadway or plot of land may someday have electrical infrastructure on it. It is also hoped that the planning and approval authorities will see that broad community input was included upfront on “the big picture” look at the valley’s electrical system as a whole. Of course, any individual project contemplated by Idaho Power will need to go through further public review and approval before plans are finalized. As mentioned in the Treasure Valley Electrical System Capacity section, two alternatives exist to reinforce the valley’s electrical system without bringing in a new source from outside the valley.

Idaho Power Company


The first is to tap the existing Boise Bench–Brownlee 230 kV transmission line somewhere in the Pearl area, and the second is to tap the Midpoint–Summer Lake 500 kV transmission line near Melba. The first option adds 400–500 MW capacity to the valley, while the second adds about 800 MW. Which reinforcement to build first will be determined based on right-of-way access issues, costs, and externalities such as integration of new generation built outside the valley. This improvement must be built and on-line prior to 2012 to ensure that the Treasure Valley’s electrical reliability remains at an acceptable level. The first reinforcement will likely be followed a few years later by the other option described above. After the reinforcement options are built, the next project’s timing and location will be dictated by the Treasure Valley’s growth. Following completion of the present study, a 10-year planning activity will be initiated to determine which lines and substations, and the timing associated with them, are next in the cue. Plans will also be made for new sources to feed the valley from outside the area and interconnect to planned 500 kV Source Substations.

Conclusions/Results The TVEP lays out high-voltage transmission and substation infrastructure from now through valley build out. In a cooperative effort with the CAC, the plan determines locations for major substations and transmission lines serving the valley for many years to come and allows Idaho Power to plan individual projects without being concerned that those projects will not fit into future plans. Individual projects resulting from this plan will still require jurisdictional approval and will be put through a careful, public process. This first step, however, will give the jurisdictions and citizens a heads-up as to where electrical equipment will be located and allow them to plan accordingly. In preparing the TVEP, Idaho Power has taken into account the affect that demand-side management will have on future load in the Treasure Valley. Idaho Power is committed to reducing electrical load in the Treasure Valley through the use of demand-side management at all customer levels, from residential to industrial. In conjunction with activities outside Idaho Power’s control—such as expected improvements in Idaho building standards, customer involvement, and energy efficiency technology advancements—Idaho Power expects new electrical load to be reduced by 20 to 30 percent. Idaho Power demand response programs will also help reach these goals. The TVEP gives approximate locations for 5 Source Substations and 15 Hub Substations. It also provides approximate right-of-way corridors for over 275 miles of 230 kV transmission and 160 miles of 500 kV transmission. The total cost at build out for all this infrastructure is nearly a half billion dollars in 2006 terms. Future changes in technology may make many of these lines and substations unnecessary or, at least, delay their need. These types of shifts, however, are impossible to predict; therefore, Idaho Power can only monitor them and understand that no matter how good the present plans are, external forces can change them.

Idaho Power Company


With so much infrastructure addition planned, it is imperative that Idaho Power attempt to acquire substation sites and right-of-way corridors before they are needed. The rapid growth in the Treasure Valley is making it difficult to find land or right-of-way easements and, when they can be found, the price is often prohibitively high. Idaho Power prefers not to buy land or obtain easements until they are needed; however, in the special case of the Treasure Valley, early arrangements are necessary for many substation sites and transmission line corridors. With the TVEP in place, Idaho Power can evaluate future land needs and make land purchases or obtain easements as necessary. The TVEP is also flexible enough that substation sites and transmission line corridors can be shifted somewhat to accommodate land availability. Transmission lines are often located alongside road rights-of-way, and many planning activities are taking place in the Treasure Valley that will significantly change many roads in the future. Idaho Power is actively involved in the Blueprint for Good Growth study in Ada County, as well as the Communities in Motion plan for the six counties that make up southwest Idaho. Idaho Power also actively engages the ITD, the Ada County Highway District, and the various highway districts in Canyon County, tracking any road changes that might affect electrical infrastructure. Through coordination with valley planning activities and transportation agencies, it is hoped that Idaho Power can influence road corridor widths so that they can include electrical infrastructure alongside. The TVEP gives a long-range idea of which roads are important to Idaho Power. The job now is to put this plan into action. The first step is to build the two system reinforcements identified in the northern and southern parts of the Treasure Valley. These reinforcements will buy Idaho Power time while it plans major new transmission projects that will feed power to the valley. Of course, actions external to the Treasure Valley can modify the timing of any plans that are in place. If a new power plant is built before the reinforcements are built, a major new transmission line from the power plant to the valley might be required that would supersede a reinforcement project. The beauty of a build-out plan is that it can accommodate these types of changes. The substations and transmission lines are already planned; only their timing is affected.

Idaho Power Company


This page left blank intentionally.

Idaho Power Company

October 2006 Treasure Valley Electrical Plan Appendix A—Page 1

Appendix A—List of Community Advisory Committee Members

Dave Aspitarte Eagle Planning and Zoning Commissioner

Teri Bath Eagle Chamber of Commerce

Matt Beebe Canyon County Commissioner

Kevin Bayhouse Member of the Public

Shirl Boyce Boise Metro Chamber of Commerce

Susie Brocke Member of the Public

Anna Canning Planning Director, City of Meridian

Elaine Clegg Boise City Council Member

Richard Cook Ada County Planning and Zoning Administrator

Dave Dykstra Windermere Real Estate

Matt Ellsworth Planning Department, City of Meridian

Kelli Fairless Executive Director, Valley Regional Transit

John Franden Commissioner, Ada County Highway District

James Grunke Boise Metro Chamber of Commerce

Brad Hawkins-Clark Principal City Planner, Meridian

Ken Jantz Member of the Public

Kathleen Lacey Chief, Comprehensive Planning City of Boise

Miguel Legarreta Government Affairs Director, Building Contractor’s Association of SW Idaho

Nosh Makujina Simplot

Mike McGown Regional Administrator, Idaho Department of Environmental Quality

Frank McKeever Middleton Mayor

Bryce D. Millar Commissioner, Nampa Highway District #1

Nathan Mitchell Star Mayor

Garret Nancolas Caldwell Mayor

Dean Obray Kuna Mayor

Stan Olson Olson & Associates Architects, P A

Bruce Poe Cole Poe Architects

Allan Perman Facilities Electrical Engineering Supervisor, Micron Technology, Inc.

June Hues Department of Environmental Quality

Paul Raymond Public Works Director, Nampa

Jayson Ronk Government Affairs Director, Building Contractor’s Association of Southwest Idaho

Hal Simmons Planning Director, Boise

Matthew Stoll Executive Director, Community Planning Association of Southwest Idaho

Fred Tilman Ada County Commissioner

John Tomkinson Ada County Planning and Zoning

John Velikoff Facilities Engineering Manager, Micron Technology, Inc.

Donna West Executive Director of Development Services, Canyon County

Charles Winder Board Chairman, Idaho Transportation Department

Idaho Power Company

October 2006 Treasure Valley Electrical Plan Appendix B—Page 1

Appendix B—Comments & Suggestions Recorded During Mapping Exercises

Workshop #1 – Wednesday, March 22, 2006 Committee Attendance: Group #1

• Mike McGown • Paul Raymond • Toni Tisdale • John Velikoff

Questions asked by the group:

• Why do different utility companies use different voltages? • Why are switching stations needed? • Why is a new transmission line needed from the Mora substation to Mountain Home? • Can we go beyond the Treasure Valley and hide the 500 kV line in the mountains? • Do the final buildout numbers include Emmett? • Where are buildout lines and what areas are restricted? • Does the 500 kV line have to create a full circle? • Can the 500 kV line extend into Oregon? Is that a benefit? • Is there a value to incorporating proposed future hub substations into the 500 kV line? • Is it hard to cross a river with a 500 kV line?

Issues important to the group:

• Want to hide the 500 kV line as much as possible using geography • Want to use existing lines to connect source substations to the new 500 kV line. • Want to focus more substations in the eastern end of the valley • Want to connect new source substations with 238 kV lines • Used mostly existing right-of-way with double circuits

Idaho Power Company

October 2006 Appendix B—Page 2 Treasure Valley Electrical Plan

Workshop #2 – Thursday, March 23, 2006 Committee Attendance: Group #2 Group #3

• Lance Evans • Carl Miller • Ken Jantz • John Tomkinson • Kathleen Lacey

• Nathan Mitchell • Bruce Poe • June Hues • Fred Tilman • Frank McKeever

Questions asked by Group #2

• Is there a chance of getting right-of-way from PacifiCorp? • Can you cross a river? • Can transmission lines be placed in hills or steep country? • Can you convert a 500 kV to 138 or 230? • Is the rail corridor preserved by the Nampa hub substation for right-of-way or has it been

sold? • What is the width of right-of-way for a 230 kV?

Issues important to Group #2

• Lines should already be placed before growth occurs so they don’t surprise people • Try to use existing right-of-way so you don’t interrupt any land • Want to follow right-of-way by PacifiCorp • Follow the new Highway 95 for the 500 kV line • Want to use the least amount of turns and corners • Stay away from ridgelines • Two options for the 500kV line: Go straight through the small town or go around the

small town (refer to map) • Want to move the line to Simplot Road in Caldwell because it is an industrial area vs. a

residential/farmland area • Want to double-circuit any line they can

See Group #2 map for results of mapping exercise Questions asked by Group #3:

• Should there be more or fewer source substations? • Cost – how expensive are things? • Does the 500 kV have to loop the valley? • Can you go into Oregon? • How much electricity can be on each pole?

Issues important to Group #3:

• Look at corners of the valley to place source substations • Use existing infrastructures as much as possible

Idaho Power Company


• Use the PacifiCorp. line as much as possible • Don’t worry about height of lines—if there is a 230, go to 500 • Community members may have problems with raising the height of an existing

transmission line • Put source substation next to landfill • Having the flexibility to move • Use the U.S. 95 corridor in the western Treasure Valley to run the 500 kV line north and

south • Assuming source is coming to the valley from north and southwest • Don’t go too close to Emmett bench on north side • Stay east of Garnett Road • Miss the houses on U.S. 95 • Best route with least impact – don’t go through downtown • Double-circuit a lot of lines • Consider cost • Try to create least impact to high-density areas and urban centers – balancing it with the

need to ring the valley with transmission lines • A criticism of the plan is that it is a 30-year strategy, but technology may develop faster

and the need for this infrastructure may go away. • However, the corridors may still be necessary at the macro level for energy distribution.

Idaho Power Company


Workshop #3 – Friday, March 24, 2006 Committee Attendance: Group #4 Group #5

• Dave Aspitarte • Jennifer Maldonado • Bonnie Ford-LeCompte • Stan Olson • Bill Vaughn

• Anna Canning • Matt Ellsworth • Tricia Nilsson • John Franden • Bryce Millar

Questions asked by Group #4:

• Does Idaho Power need to have easy or daily access to the source substation? • Can they cross a river?


• Co-location of transmission lines • Avoid ridge tops • Put the source substations in a valley • Place the 500 kV line south of the bluffs by Emmett • Don’t want a source substation in the view shed in Canyon County, especially in the Lake

Lowell area • Wanted to push the source and hub substations more to the west • Would like to upgrade several 138kV lines to 230 kV lines. • Use Highway 16

Questions asked by Group #5:

• What to start with? • What is Pearl? Why do you call it Pearl? • Can you go into Oregon? It’s not as developed. • How difficult is it to cross the river with transmission lines?


• Run transmission lines through the draws so the whole valley does not see • The weigh stations and rest areas might be worthwhile to locate source substations • Look at U.S. 95 to go north and south • Go around Wilder if you use U.S. 95 • Really tried to avoid developed areas for 500 kV • Struggled with the north–south connection in Treasure Valley at the west end • Use existing right-of-way as much as possible • Need to serve industrial customers too • Co-locate – roads, bike paths, multi-use • Use Highway 16 • Consider density and future growth

Idaho Power Company


• 500 kV o Loop needed o Use PacifiCorp line o Don’t worry about the foothills o Connect transmission lines with the west end of valley going north–south o Locate soon, before land is developed

• 230 kV o When locating 230 kV lines, upgrade/expand existing lines as much as possible

• Source Substations o More than four o Locate soon, before land is developed

• Hub substations o When locating hub substations, expand existing substations as much as possible

Idaho Power Company


Workshop #4 – Tuesday, March 28, 2006 Committee Attendance: Group #6

• Shirl Boyce • Richard Cook • James Grunke • Ray Stark • Nancy Vannorsdel

Questions asked by the group:

• Can we cross into the State of Oregon? • Does Idaho Power need to have easy or daily access to the source substation? • Can they cross a river? • Does Idaho Power have the power of eminent domain?

Issues important to the group:

• Communicate again and again with new players – elected officials, local jurisdictions, planning staffs

• Regardless of configuration: o Develop an abbreviated plan that is reader-friendly and make sure you share it with

the public o Do your best to communicate the plan’s parameters o Make sure people understand the plan o Keep reminding people, leadership, communities, and local planning staffs of the plan

• Would like to use the existing infrastructure as much as possible • Might have to use eminent domain • Place lines in the identified areas that will be developed in the future but are not

developed yet, so people are used to looking at the lines before they move in • Consider planned communities in southeast Boise in the planning process

Idaho Power Company

October 2006 Treasure Valley Electrical Plan Appendix C—Page 1

Appendix C—Load Density Based on Zoning

City Area Comp Zone kW/

Sq Mile Res.

Lots/Acre

Boise WEST BENCH RURAL DENS 2,560 1 Boise FOOTHILLS ESTATE DENS 2 5,120 2 Boise FOOTHILLS SLOPE PROTECT 2,560 1 Boise SOUTHWEST ESTATE DENS 3 7,680 3 Boise NORTHWEST HIGH DENS 43 7,680 3 Boise NORTHWEST LOW DENS 4 10,240 4 Boise SOUTHEAST PLANNED COMM 10,240 4 Boise WEST BENCH LOW DENS 6 15,360 6 Boise WEST BENCH TOWN LOT DENS 8 15,360 8 Boise WEST BENCH MED DENS 15 28,800 15 Boise NORTHWEST MED DENS 15 28,800 15 Boise NORTH/EAST END MED DENS 15 28,800 15 Boise CENTRAL BENCH MED DENS 15 28,800 15 Boise SOUTHEAST MED DENS 15 28,800 15 Boise SOUTHWEST MED DENS 15 28,800 15 Boise NORTHWEST HIGH DENS 43 82,560 43 Boise NORTH/EAST END HIGH DENS 43 82,560 43 Boise WEST BENCH HIGH DENS 43 82,560 43 Boise CENTRAL BENCH HIGH DENS 43 82,560 43 Boise SOUTHEAST HIGH DENS 43 82,560 43 Boise AIRPORT AIRPORT 2,500 Boise SOUTHWEST AIRPORT Boise SOUTHWEST ARPT CONSERVE Boise AIRPORT ARPT CONSERVE Boise FOOTHILLS BUILDABLE 4,277 1 Boise SOUTHWEST COMMERCIAL 34,452 Boise NORTHWEST COMMERCIAL 34,452 Boise WEST BENCH COMMERCIAL 34,452 Boise FOOTHILLS COMMERCIAL 34,452 Boise NORTH/EAST END COMMERCIAL 34,452 Boise CENTRAL BENCH COMMERCIAL 34,452 Boise SOUTHEAST COMMERCIAL 34,452 Boise AIRPORT COMMERCIAL 34,452 Boise NORTHWEST COMMERCIAL 34,452 Boise NORTH/EAST END INSTITUTIONAL 70,101 Boise CENTRAL BENCH INSTITUTIONAL 70,101 Boise SOUTHEAST INSTITUTIONAL 70,101

Idaho Power Company

October 2006 Appendix C—Page 2 Treasure Valley Electrical Plan


Sq Mile Res.

Lots/Acre

Boise NORTHWEST MIXED USE 34,452 Boise WEST BENCH MIXED USE 34,452 Boise DOWNTOWN MIXED USE 34,452 Boise CENTRAL BENCH MIXED USE 34,452 Boise NORTH/EAST END MIXED USE 34,452 Boise NORTHWEST OFFICE 20,671 Boise WEST BENCH OFFICE 20,671 Boise NORTH/EAST END OFFICE 20,671 Boise FOOTHILLS OFFICE 20,671 Boise WEST BENCH OFFICE 20,671 Boise CENTRAL BENCH OFFICE 20,671 Boise SOUTHEAST OFFICE 20,671 Boise AIRPORT OFFICE 20,671 Boise NORTHWEST OPEN SPACE Boise FOOTHILLS OPEN SPACE Boise WEST BENCH OPEN SPACE Boise NORTH/EAST END OPEN SPACE Boise DOWNTOWN OPEN SPACE Boise CENTRAL BENCH OPEN SPACE Boise SOUTHEAST OPEN SPACE Boise SOUTHWEST OPEN SPACE Boise FOOTHILLS PUBLIC FACILITY Boise NORTH/EAST END PUBLIC FACILITY Boise AIRPORT PUBLIC FACILITY Boise SOUTHWEST PUBLIC FACILITY Boise WEST BENCH PUBLIC FACILITY Boise NORTHWEST SCHOOL 1,000 Boise WEST BENCH SCHOOL 1,000 Boise FOOTHILLS SCHOOL 1,000 Boise NORTH/EAST END SCHOOL 1,000 Boise DOWNTOWN SCHOOL 1,000 Boise CENTRAL BENCH SCHOOL 1,000 Boise SOUTHEAST SCHOOL 1,000 Boise SOUTHWEST SCHOOL 1,000 Eagle Residential Estate 1,280 0.5 Eagle Residential Rural 1,280 0.5 Eagle Transitional Residential 1,280 0.5 Eagle Residential One 2,560 1 Eagle Residential Two 5,120 2 Eagle Residential Three 7,680 3 Eagle Residential Four 10,240 4

Idaho Power Company

October 2006 Treasure Valley Electrical Plan Appendix C—Page 3


Sq Mile Res.

Lots/Acre

Eagle High Density Residential 82,560 43 Eagle Business Park 34,452 Eagle Central Business District 34,452 Eagle Commercial 34,452 Eagle Eagle Island Special Use Area 0 Eagle Industrial 43,065 Eagle Mixed Use 34,452 Eagle Professional Office 20,671 Eagle Public/Semi-Public 0 Eagle Village Center 34,452 Garden City low res 10,240 4 Garden City med res 15,360 6 Garden City high res 82,560 43 Garden City city park 0 Garden City commercial 34,452 Garden City county park 0 Garden City ind/tech park 43,065 Garden City mix 34,452 Garden City office 20,671 Garden City open space 0 Garden City water 0 Meridian Very Low Density Residential 5,120 2 Meridian Low Density Residential 10,240 4 Meridian Medium Density Residential 15,360 6 Meridian High Density Residential 82,560 43 Meridian Commercial 34,452 Meridian General Industrial 43,065 Meridian MU-C 7,680 3 Meridian MU-N 7,680 3 Meridian MU-RG 7,680 3 Meridian MU-WWTP 7,680 Meridian Office 20,671 Meridian Old Town 10,000 Meridian Public Meridian Public Park Meridian Public School 1,000 Nampa Ag 1,280 0.5 Nampa Rural_Res 5,120 2 Nampa LD_Res 10,240 4 Nampa HD_Res 82,560 43 Nampa Commercial 34,452

Idaho Power Company

October 2006 Appendix C—Page 4 Treasure Valley Electrical Plan


Sq Mile Res.

Lots/Acre

Nampa Heavy_Industrial 43,065 Nampa Light_Industrial 43,065 Nampa MD_Res 11,880 8 Nampa Office 20,671 Nampa Parks Nampa Public

Ada Ag 1,920 0.5 Canyon Ag 1,920 0.5 Caldwell Nampa Average 16,141 3.084 Kuna 11,880 4 Middleton 11,880 4 Star 11,880 4 Gov Land GOV 1,920 0.5 Water WATER 1,920 0.5

Land/Load Based Land/Cust Based

7,197,183 kW 1,061,872 lots 2,399,061 people 2,654,679 people

2,389,211people assuming

a 90% land usage

rate in residential zones (golf courses, park…esc) 7,964,038 kW or 7,167,634 kW

Idaho Power Company

October 2006 Treasure Valley Electrical Plan Appendix D—Page 1

Appendix D—Group Mapping Results

Idaho Power Company

October 2006 Appendix D—Page 2 Treasure Valley Electrical Plan


Idaho Power Company


Idaho Power Company


Idaho Power Company


Idaho Power Company


Idaho Power Company


Idaho Power Company


Idaho Power Company

October 2006 Treasure Valley Electrical Plan Appendix E—Page 1

Appendix E—Group Drawings Similarities/Commonalities

Idaho Power Company

October 2006 Appendix E—Page 2 Treasure Valley Electrical Plan


Idaho Power Company


Idaho Power Company


Idaho Power Company


Idaho Power Company


Idaho Power Company


Idaho Power Company


Idaho Power Company


Idaho Power Company

October 2006 Treasure Valley Electrical Plan Appendix F—Page 1

Appendix F—n-1 Reliability Criteria Example Idaho Power must adhere to what’s known as an “n-1” criterion.

For multiple transmission lines delivering power to the same point, if one of the lines goes out of service, the remaining lines must be able to carry both the load they were carrying before the event, plus the load carried by the line that is out of service. • This is true even if the line with the highest capacity is the one that goes out of

service. • Only holds true for major transmission lines.

Take for example three, extra-high voltage, 345,000-volt transmission lines operating electrically in parallel as shown in Figure 1. This means that they all originate in the same location and deliver power to the same location. Each line might take a different path to get there, but all three begin and end in the same locations.

Figure 1. Three Parallel Transmission Lines

The top line is 100 miles long and has a capacity of 725 MW. The middle line is also 100 miles long and has a capacity of 1,053 MW. The bottom line is 200 miles long and has a capacity of 780 MW. There is a substation located at the halfway point on the bottom line but it has no effect on the power flow.

Idaho Power Company

October 2006 Appendix F—Page 2 Treasure Valley Electrical Plan

Normal Operation, No Lines Out The three lines in Figure 2 are carrying a total of 1,400 MW to a load located at Big Town Substation. Note that the generator is producing 1,406 MW of power while the load is only consuming 1,400 MW. The difference between the two is due to losses on the transmission system—losses that must be provided for by the generator. The green arrows shown on the drawings indicate the direction of power flow.

Figure 2. Three Parallel Transmission Lines During Normal Operation

The blue circle on each transmission line is a visual indication of how much each line is loaded. The top circle indicates that the line is carrying about 75% of the amount it is capable of. If the circle turns orange, it indicates that the line is approaching its maximum capacity. A red circle indicates that the line has exceeded its capacity.

All three lines are operating within their capacity and could operate like this indefinitely. Top line capacity = 725 MW Top line operating at 526 MW Middle line capacity = 1,053 MW Middle line operating at 612 MW Bottom line capacity = 780 MW Bottom line operating at 263 MW

Idaho Power Company


Bottom Line Out of Service

Now let’s see what happens if we take the bottom line out of service. The circuit breaker located on the right side of the line (red box in upper drawing) turns to a hollow green when the circuit breaker is open, de-energizing the line.

Figure 3. Three Parallel Transmission Lines, Bottom Line Out of Service

Notice that no power flows on the bottom line now. The middle line, which has the highest capacity of all three, is now operating to about 75% of its capability. The top line indicates that it is operating at 89% of its capability, giving us a warning. However, these lines could operate like this indefinitely, so no action is required. In this case, we have met the n-1 criteria. Top line capacity = 725 MW Top line operating at 647 MW Middle line capacity = 1,053 MW Middle line operating at 753 MW Bottom line capacity = 780 MW Bottom line operating at 0 MW Note that the generator on the right side of the drawing is producing more power compared to the last case. This is because the power losses are higher with one of the lines out of service because there is more resistance to power flow.

Idaho Power Company

October 2006 Appendix F—Page 4 Treasure Valley Electrical Plan

Top Line Out of Service

Now we will put the bottom line back in service and take the top line out of service. Again, the circuit breaker on the right of the top line will go from solid red to hollow green, indicating that the line is out of service.

Figure 4. Three Parallel Transmission Lines, Top Line Out of Service

Notice that no power flows on the top line now. The bottom line indicates that it is operating at about two-thirds of its capability, while the middle line is warning us that it is operating at 93% of its capability. These two lines could operate like this indefinitely so, again, no action is required. Top line capacity = 725 MW Top line operating at 0 MW Middle line capacity = 1,053 MW Middle line operating at 979 MW Bottom line capacity = 780 MW Bottom line operating at 421 to 422 MW Again, note that the generator is now producing more power due to the higher line losses with one of the lines out of service.

Idaho Power Company


Middle Line Out of Service

The top line is put back in service and the middle line is taken out of service. This is indicated in Figure 5 by the circuit breaker located on the right side of the middle line changing from a solid red box to a hollow green box.

Figure 5. Three Parallel Transmission Lines, Middle Line Out of Service

Figure 5 indicates that the bottom line is operating at about two-thirds of its capability and can be maintained indefinitely. However, notice that the top line’s indicator shows that it is now operating at 129% of its capability. A transmission line cannot operate like this for very long because the line gets too hot and can be damaged to the point of breaking. So, in this case, our three transmission lines have failed the n-1 test. When the largest transmission line was taken out of service, the other two could not safely carry the power it was carrying plus the power they were carrying before the incident. Top line capacity = 725 MW Top line operating at 933 MW Middle line capacity = 1,053 MW Middle line operating at 0 MW Bottom line capacity = 780 MW Bottom line operating at 467 to 468 MW

Date post:	06-Sep-2020
Category:	Documents
Upload:	others
View:	1 times
Download:	0 times

Treasure Valley Electrical Plan - Idaho Power...Distribution Substation Placement Once the TVBP...

Documents